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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe8f351c8b6ceaf3cb3d366340ef69ffb5455390d6d5bdf1498ed9d9a02e5d2d' 
  AND token = 'HgpjxtCXQjhpT3HrMYhLmwhjV0uGwELDb/VzCEvOdac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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