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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3106c3f166ef1b1b6410d634c5d7fd07248594b8a779978bfa5b512f1d3ac99' 
  AND token = 'S5v5yvc/AfpO2iaqQvFYCK6Qx+WzaDYDCafhL3MvkYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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