SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '951451fd7b74d7d695e3df112fd5c01383e867e636bce6e0b0b9ec19928b8016' 
  AND token = 'tSpJ9bC4RO21lKm3CmzOiseSIEYi5PEhikrAJF/1/Jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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