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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c0b75b518e70da2b4bad0af3ed0d13115c9eb4f8fa8c4d0b7c9d426976cba690' 
  AND token = 'LUkMBhiS3LyULWk2e12k+YhHs2XsjEGsAEvplTH03UM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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