SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5369a7fb4224e7c118dab3bb1eb646c264697af2abf4a1a39b80edebfd632151' 
  AND token = 'a3umXDPOIounJ1/Q2Q0srXef0w9cGXjspszNIAOqsgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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