SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc931d44664fedf33e27a0720361bfdfd507f899708d20d1226399aee269fe77' 
  AND token = '1NTsrCp1VPcUPQGp86U7uj3C0QrhdD76lVcDworY8xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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