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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3138a2703cbfdbd8e3b3b4fb9693b4a9f3bd1e78c9f8fba2b18115cd762d29e3' 
  AND token = 'mEJMLMLCenQPZM/7Rlbv4LO4pFBiAUux9mxHPionRtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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