SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27514ba35497687a1a85e2429617cf6f6bb64c18661cbef22439d5181cb147cc' 
  AND token = 'mzKL28pg1D+I8cPf9sEs74fVzLVM5d4eLH8m+s5gnJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}