SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52c14ad173900743d111e4e62c9a6958f4f5828ff0cdb9477ca3551859ab407a' 
  AND token = 'hvasRvr4NytuH4zCG58GW6xM4AJ+aGk9G+128i1MoyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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