SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37890367c93f48024d87a837a67cbb209639b00012adadc764bb78f204d138f7' 
  AND token = 'R5TE5hYKapmYFOP1nnmE/X/M+BTdfCLzzd7fxWUrD0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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