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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f8ec5dc3addfd5da1d761ffb135f97704d7d72b6634f516c1b88b7e0dc8e79d5' 
  AND token = 'BIQ2+MQKrdFloUiwT2IPnEw+3a21M9+7VC1S7tWAWDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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