SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b1dd7b7e642ab5745598252ef618751b7467c9b32518e68fbe90901279fa510' 
  AND token = 'UsZtMqie3p8EANAmCcYmFH/S+b/5plJRzNs+ZWmjY6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}