SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '321762b8b4654ababdcf2e20ac68935dd537bb931f90a522a33d7aec99ed07c5' 
  AND token = 'OqKGq1BjyAyzP/6ea4ADGer6J5o5oo+VRo1cCwSDoA0=' 
  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"
    }
  }
}