SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3ee837759b442973388d243acf3556e8a5db92d9cdef512f81e5d45c1672d1f' 
  AND token = '8vk58D0O1Qu4pqioK/tHpj+7hfv34p3aBCO48bU+f0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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