SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '210651af8841fcc2119b2297ddfe523035ea6f790e2486a9fad81e8566934cb8' 
  AND token = 'AJtHGjQ6bJWm5GpV/pW3+bsDw7o1XinBT2+kzBFK3CY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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