SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f2e3bfc36fe13424f0496aa4aab6a05b0d6d14702690623e09595e13fe1657b' 
  AND token = 'PAirxj0Uj7w3viXPR+iFKF849rYea+IlafOd0vERUIY=' 
  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"
    }
  }
}