SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a18feb81b8acc8443ebc66fbc25df2077fe96dc335fd8f1a31f311ef536f335' 
  AND token = '20fWHcNKsp6uJY9zldoGloeAbbjhLvRgjBqhWCwAGTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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