SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec5d39cc21178472d182b68314ce822d67bfde6db43d1fefe67e792f153da2a9' 
  AND token = 'mgb8v0SOy1K71OcMXTU2xBecZFr8YpwyDQJv9vLVHec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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