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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d51cb20b0e1c42b542eae454a36282708bd2c05df48296d8d420cdf1497ef4c' 
  AND token = 'rMJ85U0ODnuUvkQbtPK6fdvS7GZno2TD5X/6cW0eL9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}