SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c42ebe5fa05da80be53725967dc89be97a4ea1207ec4ec6fd2bdcbc309c6465e' 
  AND token = 'H0iX90s2mMMs8dStqVA8owKKQtDX3h4DQUy+flTtP6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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