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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff1ddbda0af999ec79176c8c98c6b7aeac77cc883eb3ba73317f676ca38331cb' 
  AND token = 'xQ9ZZuoDIhETmfFEtIkIKz8Sra2dUvsu/RKQh+yK9RQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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