SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0ef4beddd660aafedbec411ec4f5718a32077eda2c69094c2e8b5993b962577' 
  AND token = 'CP/vckDPGyvXb1C2QgdepsWxfzUfkjTX3DYXYVI0ujk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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