SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77fb0310e46454573d33947b6eec0a7eee0326058bd6b13f186733d7c6260968' 
  AND token = 'ldL86Q7XUKKHC9vWUrkgcAmSB0XJIbY4ij5+jyg+Gps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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