SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a8157a0b19d1bcbec8115326ccd6e3e6c706a03909edee4b4a196c24d2e50fa2' 
  AND token = 'y1pl8NZ6pWo6EzzLoGMfbIoDQYDmUquEVG5L6tCnatQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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