SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c73647fe89b80f4659518479692ced5546fa4969b90b4a7425be3ffd932aa302' 
  AND token = 'rBJw7rB1JiwL+xRc4sz3PyJI5ujCxAQUom3/QoCOyug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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