SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03a2be51c2bd003b1e3ab3c34acad13b7952ec2cab257045e931ae9f048cc9f0' 
  AND token = '1QW64I383J3OwpykG0/OmzbeeypkxtwS3+NHIKLswcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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