SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efdee31a349c0e75c3cc67381ee26098d69f943ace7b267b0d3606e95e528d82' 
  AND token = 'yVkhq9ase0TK3yAshFTjsnTMFtcFnraBv+s0xwXzu9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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