SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d55aefa82ad5b94a0b1de097ee55874a3772a1622c41fdcbf8274c5c4bf9490' 
  AND token = 'MVNw+Jd+OiYddxxWUYwMfrQSVSppQmp4a0UVq3nNm4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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