SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5148ab955576a0945b6756ef44259e6f42ba538e146acc4552179c9f4ee31f1' 
  AND token = 'FE3d96hRL3ZsntznhXWEEocY9WL2jvuZraOPvq7yEAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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