SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fcd7262e8fd328b907a82cf67875513551749ca46e602978013c085bd0cb5d0' 
  AND token = 'jH+a5LSBepVBKL4xpueh2uMeTJt4p30KETvnJdpADVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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