SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be6aef3be580ec26dbf9446d325188a93e9dd6d3d8968253c115a6c22f23d65a' 
  AND token = 'K1nD7i1HTm7XNI2RWyZlkPoFLCcsPLdGJMxC1qIw+gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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