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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fdc55f7b8486d6bee8512d11ec62831323e4a841b24b4ab83381643532d64392' 
  AND token = 'IyhUVHtfyDajDd/+4eamtM3CmID1luZmLbqlMpowxag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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