SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f66970083ecea5e49276285ef0df941f2d7859ce5ce7541046edf32b9ec6dd55' 
  AND token = 'NQbsZ0EMqEY+ZeCODYfF8ynx7uw8+AA6iu0vnCNmaXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}