SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02fbfa519046808ec465e5d3a99fab550ea886e809f0b3b10f038b6bfc0ab7dc' 
  AND token = 'BlzJkVji/v1sKeh4Xy3Ojo211v77vFbGGCnEwIsMmsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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