SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44bd9b2170aea49646da43751ddc876091563106b151ce1aba4cfc4f79c233f2' 
  AND token = '6cibu4hXSWk1UlBxIm1YlJa+JRI0Q1mINfk+t6FQX8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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