SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb080274308a63ea0b8fd20ac783c2358c9cb2ff822978ffbc86094504d1b37e' 
  AND token = 'SnPqIpdmIlpJwO62hopndKLc4UFs3hUj1Rz+zVhyS84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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