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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4639da30c06c5f7912d7a53521ad67d1d9049239085a7e398ac7fe632cdff4c9' 
  AND token = 'u7D4fxPTPeJ/KRW2oIoHjQmQ0MoRhXvNzEp2ozrghU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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