SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30f3945d98711bb5a800a343d75b5a80ff6694530083bb1042d35159eb90aa47' 
  AND token = 'g+0aGpfrJUrgkF+2D69PVAPFg0c1XPfVAQ3JRqXsleQ=' 
  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"
    }
  }
}